From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: Davidlohr Bueso <dave@stgolabs.net>
Cc: linux-kernel@vger.kernel.org,
Peter Zijlstra <peterz@infradead.org>,
tglx@linutronix.de, Manfred Spraul <manfred@colorfullife.com>,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH v4] ipc/msg: Implement lockless pipelined wakeups
Date: Thu, 21 Jul 2016 12:23:56 +0200 [thread overview]
Message-ID: <20160721102356.GB6323@linutronix.de> (raw)
In-Reply-To: <20160721001612.GA3066@linux-80c1.suse>
* Davidlohr Bueso | 2016-07-20 17:16:12 [-0700]:
>Just as with expunge_all and the E2BIG case, could you remove that explicit
>barrier (B) and just rely on wake_q_add?
Just did. So we have just a smp_rmb() on the reader side and the
comment talks about smb_wmb() and at the spot where we should have the
smb_wmb we have a comment why we don't have one :)
For my understanding: we need that smp_rmb() to ensure that everything
past that cmpxchg() is visible on all other CPUs so we don't have the
wakeup before we r_msg reads != -EAGAIN, right?
>Thanks,
>Davidlohr
Sebastian
next prev parent reply other threads:[~2016-07-21 10:24 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-20 15:45 [PATCH v4] ipc/msg: Implement lockless pipelined wakeups Sebastian Andrzej Siewior
2016-07-21 0:16 ` Davidlohr Bueso
2016-07-21 10:07 ` [PATCH v5] " Sebastian Andrzej Siewior
2016-07-21 10:23 ` Sebastian Andrzej Siewior [this message]
2016-07-21 19:47 ` [PATCH v4] " Davidlohr Bueso
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